Digging deep

The probe will hurl itself into one of the permanently shadowed lunar craters.

At impact, the spacecraft will be travelling at approximately 2.5 kilometres per second, or 9000 kilometres per hour.

Its impact will be a two-fold effort.

First the craft's second stage rocket, having detached from the probe 10 hours earlier, will slam into the Moon and be followed just minutes later by the probe. This will allow the scientific instruments to burrow as deep as possible.

In total, NASA says, the two impacts will excavate some 500 tonnes of lunar material.

The US$79 million (A$98 million) effort will culminate in searching the crater for signs of a possible long-frozen water source and examining the unseen world's mineral makeup.

Close up view

The Lunar Reconnaissance Orbiter (LRO) will conduct a one-year study of the Moon at an orbit of about 50 kilometres - the closest any spacecraft has orbited.

LRO's US$500 million (A$625 million) mission is designed to provide NASA with maps of unprecedented accuracy, which will be crucial for scoping out possible landing sites.

Both missions, says May, will help NASA model the nuances of lunar lighting and temperature range, and provide future moon travellers with information on the cosmic radiation the Moon is exposed to due to its lack of atmosphere.

May says, both missions promise to reveal "the process that formed the earth, the moon and the solar system."

The agency hopes the probes will answer a full plate of fundamental questions of cosmic history.

"LRO will send back pictures daily on things we have barely seen before," says May.

The launch of the lunar-bound spacecraft had been pushed back a day to accommodate the delayed shuttle Endeavour, which will dock with the International Space Station.

Endeavour's launch was delayed because of a hydrogen leak in an external fuel tank.

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